When a device that has a transmitter and a receiver such as, e.g., a mobile telephone, is very far away from a base station, the transmitter transmits a transmit signal having a maximum transmission power, but at the same time, a receive signal received by the receiver, e.g. a signal transmitted by the base station, is very weak. In such a scenario, a transmitter of simple structure can interfere with the receive signal or degrade the receive signal with a high noise level.
Furthermore, the higher the transmit bandwidth, the smaller will be the relative spacing between the transmit band and receive band. In the case of wideband systems, it thus becomes more and more difficult not to have interference between the receiver and the transmitter. Furthermore, the power consumption increases proportionally to the transmit bandwidth. In addition, it is necessary to increase the sampling frequency, resulting in a quadratic increase in the power consumption overall.